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Improving the equivalent-photon approximation in electron--positron collisions

Gerhard A. Schuler
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Abstract

The validity of the equivalent-photon approximation for two-photon processes in electron--positron collisions is critically examined. Commonly used forms to describe hadronic two-photon production are shown to lead to sizeable errors. An improved two-photon luminosity function is presented, which includes beyond-leading-logarithmic effects and scalar-photon contributions. Comparisons of various approximate expressions with the exact calculation in the case of the total hadronic cross section are given. Furthermore, effects of the poorly known low-Q2 behaviour of the virtual hadronic cross sections are discussed.

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Gerhard A. Schuler. 1996-10-18. Improving the equivalent-photon approximation in electron--positron collisions. https://arxiv.org/abs/hep-ph/9610406

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